John henry hamilton



Patented Mar, 2'I,-|899l.

.1. H. HAMILToN.

GAS MUTUR ENGINE.

(Application led Dec. 28, 1897A (No Model.)

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UNTTED STATES PATENT EETOEo JOHN HENRY HAMILTON, OE sANDIAORE, ENGLAND.

SPECIFICATION forming part of Letters Patent N o. 621,526, dated March 21, 1899. Application nea Detente 28,1897. seria No. 663,842. (No man.)

T LtZZ whom, it may concern:

Be it known that I, JOHN HENRY HAMILTON, a subject of the Queen of Great Britain and Ireland, and a resident of Sandiacre, in the county of Derby, England, have invented certain new and useful Improvements in Gas Motor-Engines, (for which I have obtained-a patent in Great Britain, No. 21,120, dated November 7, 1893,) of which the following is a specification.

This invention relates to four-stroke-cycle gas-engines of the scavenger-charge kind, for which a British patent, No. 6,015 of 1890, was granted to me. In these engines a charge of air is employed to scavenge or sweep out the products of combustion from the motorcylinderafter each working stroke, a two-di` ameter or differential piston Working in cylinders of two diameters placed in line with each other serving as both motor and airpump, being adapted to draw air into the larger part of the cylinder during the. out- Ward stroke and discharge it through the combustion-chamber during the exhauststroke or a part thereof; and the essential feature of this invention is the combination of such a differential piston and cylinder and another mot-or cylinder and piston placed in line or tandem with the differential cylinder, the piston of the second motor-cylinder being connected to Vthe enlarged end of the differential piston by means of rods at each side, and the space in the air-pump being in communication with the back of the admission-valves of both motor-cylinders by meansof a passage, preferably consisting in part of a detachable tube adapted to act when in place as a tie between the motor-cylinders.

The valve-gearing is so arranged that explosions Occur alternately in the motor-cylinders. Thus instead of the air being compressed and rexpanded on each alternate stroke of the aip-pump it is discharged on each back stroke-viz., through the combustion-chamber of the front motor-cylinder on one back stroke and through that of the rear motor-cylinder on the next back stroke. All the valves may be operated from one side shaft.`

I will now proceed to describe my invention with reference to the accompanying drawings, in which-mA Figure l represents a horizontal sectional elevation, and Fig. 2 a sectional plan, of a gasengine constructed in accordance therewith.

TWO motor-cylinders K and L are placed in line with each other and with another larger cylinder M, in which works th'e enlarged end A of the front piston A. The latter carries the gudgeon or pin C, to which 'is jointed the connecting-rod. It has also secured toit the side rods B B, the latter being preferably in the horizontal axial plane, as illustrated. These side rods are connected, as shown, to the large end A of piston A (the function of which, as above stated, is to act as an airpump) and pass backward alongside the motor-cylinder L, preferably through spaces in the jacket thereof, as illustrated, and are connected at their rear ends to the crosshead D, which may be cast in one with the back motor-piston P or secured to the latter by bolts. The ends of this cross-head may be provided With slippers working in guides,

as shown at E, for guiding the front end of the piston P.v

The air-inlet may be a'grid flap-valve of the kind described in my British complete Specication No. 6,015 of 1890. It is shown at F, and consists of grids g, every alternate one of which has bolted to it a flexible strip ct, of india-rubber or the like, of sufficient width to cover-the openings between the next adja` cent grids. to the cylinders K, L, and M.

The part T of the air-passage between the cylinders K and L may be removable, so as to allow of the easy withdrawal of the piston P, and when in place it forms a top tie for holding the cylinders together.

The admission-valves vfor gas .and air are shown at G and G and the exhaust-valves at H H'. These may be of any suitable kind.

`The former may be advantageously arranged as described in my British complete Specification No. 4,189 'of 1892, and both admission and exhaust valves may be operated from A passage X X conducts the air one side shaft through cams and levers in the `usual Way, the cams and operating mechanism being arranged so that when one piston is making its explosion-stroke the -other is making its suction-stroke.

The action of the engine is as follows: Supposing the pistons to be commencing their forward stroke, as shown, and that this is the explosion-stroke of the rear piston P and the suction-stroke of the front piston A,air is then drawn in thro ugh the valve F,part of it passing through the valve G to the front motor-cylinder and part to the annular space Y behind the enlarged end A of the piston A. On the return stroke, the exhaust-valve I'I of the cylinder K being opened, the admission-Valve G' being also opened after the pistons have made a portion of the return stroke, the air in the space Y is first slightly compressedsay to two pounds per square inch above atmospheric pressure-an d then passed through the valve G into the cylinder K, mixing with and expelling the products of combustion therefrom. The exhaustvalve II is not closed till after the crank has passed the deadcenter, thus allowing time for the pressure in the cylinder K and space Y to fall nearly to atmospheric pressure. The gas-valve of the cylinder K is now opened and the same series of operations are repeated, only that the front cylinder now makes its explosionstroke and back cylinder its suction-stroke.

There is thus an explosion at each forward,

stroke when working at full power.

As the scavenging charge of air is discharged through the combustion-chamber of one or other of the motor-cylinders at each re turn stroke, such a large clearance-space as is described in my specification No. 6,015 of 1890, above referred to, is unnecessary; but I prefer to make the clearance-space such that the admission-valves of the motor-cylinders need not be opened before nearly half the exhaust-.

stroke has been completed.

As the pressure in the space Y is always low, stuffing-boxes for the rods B B are unnecessary. The said rods may Work through long bushes V V instead, and these bushes may have light spring packing-rin gs inserted.

It is obvious that the two motor-pistons might be connected. directly by one central rod passing through a stuffing-box in the back end of the front motor-cylinder; butI consider the arrangement above described to be the best.

I would here state that I do not lay any claim to the mere use of side rods for connecting tandem pistons with the object of avoiding the known difficulty of packing y glands for piston-rods extending through the motor-cylinder, as that is in itself old.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A gas motor-engine of the four-stroke- .cycle type having a differential cylinder and piston adapted to serve as motor-cylinder and air-pump, a second motor cylinder and pis- `ton and means for reciprocating both the pistons simultaneously, admission and exhaust valves forboth the motor-cylinders and means for operating them, combined for the pur- -poses described with a passage for placing both admission-valves in communication with the air-pump of the differential cylinder and an'air-inlet valve, the engine being so arranged that air is admitted to the air-pump during the outward stroke and during the inward stroke compressed and discharged through the combustion-chamber of that cylinder from which the spent gases are being exhausted substantially as and for the purposes described.

2. A gas motor-engine of the four-strokecycle type having a motor-cylinder, a piston, having an enlarged cylindrical end, and means for reciprocatingI it,i admission and exhaust valves therefor and means for operating them, and a second cylinder in line with the first, combined for the purposes described, with a piston having a cross-head such asD formed on it or attached to it and arranged as specified, andside rods secured at one end to the cross-head and at the other end to said enlarged part of the iirstmotor-piston all adapted to operate substantially as described.

3. A gas motor-*engine of the four-strokecycle type, consisting of the combination for the purposes described of a motor-cylinder such as L, a larger cylinder M, a differential piston A adapted to work in both cylinders L and M, a second cylinderKin line with the first cylinder L, a piston P workingin cylinder K, a cross-head D on said piston P, side rods B B for connecting the pistons A and P and means for reciprocating the said pistons, admission and exhaust valves to both motorcylinders, a passage I leading from the space Y in the cylinder M through a passage T preferably in the form of a detachable tube to the admission-valves of the motor-cylinders and a valve F for admitting air to passageX and space Yall arranged and combined, substantially as described.

4. A gas motor-engine of the four-strokecycle type having a differential cylinder and piston adapted to serve as motor-cylinder and air-pump, a second motor cylinder and piston, admission and exhaust valves for both the motor-cylinders, and means for operating them alternately at the proper times, combined for the purposes described with a passage for placing both admission -Valves in communication with the air-pump of the differential cylinder, and an air-inlet valve, the parts of the engine being so arranged that air, admitted to the air-pump during the outward stroke, is during the inward stroke, compressed and discharged through the coinbustion-chamber of that cylinder from which the spent gases are being exhausted, substantially as and for the purposes described.

5. In a gas motor-engine of the four-stroke type, the combination of two motor-cylinders placed tandemwise, the front cylinder having an enlarged fore end, a differential piston having an enlarged front end, working in said enlarged fore end of the front cylinder and acting as an air-pump for discharging a scavenger air charge alternately through the combustion-chamber of both motor-cylinders,

IOO

IIO

a cross-head connected to the rear piston, side rods connecting the enlarged end of the front piston and the cross-head of the rear piston and passing through passages in the front motor-cylinder or its jacket, admission and exhaust valves for both motor-cylinders and mechanism for operating same at the proper times, substantially as above deseribed 6. A gas motor-engine of the four-strokecycle type, consisting of the combination for the purposes described of a vm0toreylinder such as L, a larger cylinder M, a differential piston A A adapted to Work in both cylinders L and M, a second motor-cylinder K in line with the rst motor-cylinder L, a piston P Working in cylinder K, fitted with a crosshead D, lside rods B 'B for connecting the piscylinder M through a passage T, preferably f in the vform of a detachable tube, to the admission-Valves of the motor-cylinders K and L, and a valve F for admitting air to the passage X and space Y, all arranged and com-V bined, substantially as described.

In Witness whereof I have hereunto set my hand in the presence of two Witnesses.

- JOHN HENRY HAMILTON.

Witnesses: y

HAROLD G. NIGHTNGALE, THos. HEATH. 

